ACTG 226 is a phase I, open-label, dose-escalating trial of oral ganciclovir in HIV-infected children aged 2 mths-20 yrs with asymptomatic cytomegalovirus (CMV) and low CD4 cell counts or with quiescent CMV disease. The purposes of this study are to evaluate the pharmacokinetics, long-term safety and tolerance, and maximum tolerated dose of oral ganciclovir in HIV-infected patients, and to evaluate the effect of oral ganciclovir on the virologic parameters of CMV.